does not work with hogfather

[ingof]

After updating to hogfather on my Synology the plugin is failing.

i get following error:
Fatal error: Declaration of syntax_plugin_cellbg::handle($match, $state, $pos, &$handler) must be compatible with dokuwiki\Extension\SyntaxPlugin::handle($match, $state, $pos, Doku_Handler $handler) in /volume1/web/dokuwiki/lib/plugins/cellbg/syntax.php on line 0